Immunomodulatory Effects of Ethanolic Rhizome Extracts of Drynaria quercifolia (L.) J. Sm and Curcuma aeruginosa Roxb. on Inflammatory Gene Expression in Non- induced THP-1 Monocytes

Macrophages play a central role in the inflammatory processes associated with gout, particularly through the production of pro-inflammatory cytokines in response to monosodium urate (MSU) crystals. The present study investigated the cellular immunomodulatory effects of ethanolic rhizome extracts of Drynaria quercifolia and Curcuma aeruginosa using a human THP-1 monocytic cell model under non-induced conditions. Cytocompatibility was first assessed using the MTT assay, and sub-cytotoxic concentrations were selected for downstream analysis. Both extracts exhibited concentration-dependent cytotoxicity, with IC₅₀ values of 40.94 µg/mL and 48.18 µg/mL, respectively. At a sub-cytotoxic concentration (20 µg/mL), the transcriptional modulation of key inflammatory mediators, including TNF-α, IL-6, COX-2, and iNOS, was evaluated using RT-qPCR. Both extracts significantly downregulated TNF-α, IL-6, and COX-2 expression relative to untreated controls. In contrast, iNOS expression was upregulated, with a more pronounced effect observed for D. quercifolia. These findings indicate a differential regulation of inflammatory gene expression in THP-1 cells under basal conditions. Thus, the results suggest that the rhizome extracts exhibit intrinsic immunomodulatory activity rather than direct anti-inflammatory effects in the absence of external inflammatory stimulation. This study provides preliminary evidence that these rhizome extracts possess intrinsic immunomodulatory activity in non-induced THP-1 monocytes and warrant further investigation in disease-relevant inflammatory models.